Bug:[Smartswitch] Issue with Smartswitch Vnet test case in tests/dash/test_dash_smartswitch_vnet.py

[gpunathilell]

Is it platform specific

generic

Importance or Severity

Critical

Description of the bug

This bug is created to indicate all the issues with the test_smartswitch_outbound_vnet present in tests/dash/test_dash_smartswitch_vnet.py in sonic-mgmt: https://github.com/sonic-net/sonic-mgmt/blob/master/tests/dash/test_dash_smartswitch_vnet.py
Currently the attributes requried for the VNET test case cannot be configured since there are private link specific attribtues configured by default which causes metadata check failure in sairedis. To be fixed by the PR:
sonic-net/sonic-swss#4031 (Pending review)
Other issues in the test:

Packet is sent with VNET1_VNI instead of VM_VNI: https://github.com/sonic-net/sonic-mgmt/blob/93d536205cadce8fc02f34a0607f8707b353aeff/tests/dash/packets.py#L516.
Packet TTL expected is 63, On Nvidia Platform the received value is 254: https://github.com/sonic-net/sonic-mgmt/blob/93d536205cadce8fc02f34a0607f8707b353aeff/tests/dash/packets.py#L527
The packet's the vni is not configured as part of the trusted vni in the appliance table: https://github.com/sonic-net/sonic-mgmt/blob/93d536205cadce8fc02f34a0607f8707b353aeff/tests/dash/templates/dash_smartswitch_vnet_0.j2#L7

After making these changes the test should be able to pass

Steps to Reproduce

Run the test in tests/dash/test_dash_smartswitch_vnet.py

Actual Behavior and Expected Behavior

Actual Behavior: Test failure
Expected Behavior: Test Pass

Relevant log output

Output of show version, show techsupport

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Attach files (if any)

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